The horn tapers from 84" inside
dimension at the large end to 12" in its 16' length. The requirements for a
smooth finish on the inside of the horn were very important. Because of the
small tapered end, it would be difficult to perform any remedial concrete
patching on the inside of the structure.
The attached pictures show the
structure being removed from the forms by a 75 ton overhead crane located
in building 65 at Wright-Patterson AFB. The structure was turned 90 degrees
in the air and set on the ground. It was then dollied into place inside a
large acoustical chamber in the Structures Research Laboratory at WPAFB
The completed sub-element chamber will be used to test experimental
materials used in jets by subjecting them to sound waves at up to 150 dB.